I know normally in a 32-bit machine the size of pointers used in regular C programs is 32-bit. What about in a x86 system with PAE?
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Are you talking about application code or kernel code? – David Heffernan Oct 15 '14 at 06:26
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@DavidHeffernan application code – Norma Barner Oct 15 '14 at 06:31
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From the app perspective pointers are still 32 bit. All the PAE specifics are on the kernel side. – David Heffernan Oct 15 '14 at 06:35
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It's still 32 bits.
PAE increases the size of physical memory addresses, which lets the operating system use more than 4GB RAM for running applications. To run an application the operating system maps the larger physical addresses to 32 bit virtual addresses. This means that the address space in each application is still limited to 4GB.
Joni
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PAE changes the structure of page tables to allow them to address more than 32 bits worth of physical memory. Virtual memory addressing remains unchanged — pointers in userspace applications are still 32 bits.
Note that this means that 32-bit applications can be used unmodified on PAE systems, but can still each only use 4 GB of memory.
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It is 32 bit only.Because,
PAE is a feature to allow 32-bit central processing units (CPUs) to access a physical address space (including random access memory and memory mapped devices) larger than 4 gigabytes.
see this http://en.wikipedia.org/wiki/Physical_Address_Extension
Anbu.Sankar
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You can access the memory through a window (address range). Each time you have to use something outside that range, you should use a system call to map another range there. Consider using multiple heaps, with an offset within the window (pointer) - then the full pointer would be the heap identifier and a window offset (structure), totally 64 bits, each time you have to go outside the current heap, you have to switch them though.
Programmer
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